PACKARD. INHERITANCE OF ACQUIRED CHARACTERS. OOJ 



known. Dr. Chapman however found a solitary specimen of the 

 young larva in the triuiigulin stage. He describes it as "a little black 

 bexapod, about ^ ti inch (.5 mm.) in length, and T .] () inch in breadth, 

 broadest about the fourth segment, and tapering to a point at the tail; 

 a triangular head with a pair of three-jointed antennae nearly as long 

 as the width of the head, with legs very like those of Meloe larvae ; 

 the tibiae ending in two or three claws, which are supported and even 

 obscured by a large transparent pulvillus or sucker of about twice 

 their length ; this was marked by faint striae radiating from the ex- 

 tremity of the tibia?, giving it much the aspect of a lobe of a fly's 

 proboscis. Each abdominal segment had a very short lateral spine 

 pointing backwards; the last segment terminated by a large double 

 sucker similar to those of the legs; and the little animal frequently 

 stood up on this, and pawed the air with its feet, as if in search of 

 some fresh object to lay hold of." 



This almost microscopic larva finds a wasp grub and bores into its 

 body, probably entering at a point near the back of the first or second 

 segment behind the head. Dr. Chapman succeeded in finding the 

 larva of the beetle within that of the wasp, before the latter had spun 

 up. " Assuming that the wasp larva lives six days in its last skin be- 

 fore spinning up, I should guess that the youngest of these had still two 

 or three days' feeding to do. The Rhipiphorus larvae were but a little 

 way beneath the skin of the back, about the fourth and fifth segments 

 [counting the head as the first], and indifferently on either side. The 

 smallest of these was T \j inch in length, and, except its smaller size, 

 was precisely like the larger ones I am about to refer to, having the 

 same head, legs, plates, etc. These were of the same size as those 

 of the larger larvae, the difference in size of the latter being due to 

 the expansion of the intermediate colorless integument." 



After the wasp grub has spun the silken covering of its cell the 

 larva of Rhipiphorus may be still detected in some of them, being 

 rendered visible by its black legs and dark dorsal and ventral plates. 

 " On extracting this larva, it bears a general resemblance in size and 

 outline to the youngest larva of Rhipiphorus that I had found feeding 

 externally on the wasp grub, but with the very notable exception of 

 the already mentioned black marks. These are, in fact, a corneous 

 head, six-jointed legs, and a dorsal and ventral series of plates. I 

 immediately recognized the head and legs as identical with those of 

 the little black mite already described, but presenting a ludicrous ap- 

 pearance in being widely separated from each other by the white skin of 

 the larva. I have no doubt that the dorsal and ventral series of black 



